Pumps including secondary air pumps are used to control the flow of fluid medium or air to an engine. In particular secondary air pumps are used for the purpose of rapidly supplying outside air to the engine catalyst during an initial start in order to raise the catalyst temperature more quickly. Secondary air pumps generally have a housing and cover that have an inlet and outlet formed in the cover. The housing together with the cover form a flow path between the inlet and outlet. An actuator is connected to the housing and engages a fan member that rotates within the flow path between the inlet and outlet. Designing ways of increasing air flow through the pump arrangement is desirable because when the design of the housing and cover can promote greater flow than it will reduce stress on the actuator. Also increasing the flow will reduce the size of the actuator required for the pump arrangement.